在碳量子点溶液中加入汞离子, 量子点的荧光被猝灭, 加入三聚氰胺后荧光恢复。据此, 建立了基于碳量子点荧光恢复测定三聚氰胺的新方法并应用于实际样品的分析。研究结果表明, 在汞离子和碳量子点浓度之比为15∶10000且碳量子点浓度为4.0 g/L、pH值为7.5的实验条件下, 方法的线性范围为3.0～60.0 mg/L, 检出限(3σ/k)为2.2 mg/L。方法应用于实际样品测定时, 其回收率为95%～103%。

We report a method for determination of melamine based on fluorescence recovery of carbon quantum dots (CQDs). It was found that the fluorescence intensity of CQDs can be efficiently quenched by Hg2+. And a turn-on fluorescence signal can be observed if melamine was added. The results showed when the concentration ratio of mercury ions to carbon quantum dots was 15∶10000, the concentration of carbon quantum dots was 4.0 g/L and the pH value was 7.5, the response was linearly proportional to the concentration of melamine within the range of 3.0-60 mg/L, the limit of detection (3σ/k) was 2.2 mg/L. The method was successfully applied to the determination of melamine in real sample with satisfactory recoveries (95%-103%)